An electrodynamic transducer is known from Italian patent application No. 2002A000245, which may be used as pressure sensor in an electric household appliance and which comprises a rigid body accommodating a deformable membrane therein, which is sensitive to the hydraulic pressure present on one side of the same connected in use, for example, to a tank of an electric household appliance containing a fluid, the level of which is intended to be measured; the membrane carries a ferromagnetic core operatively connected to an inductor and its movement thus produces a variation of the resonance frequency of the inductor which may be detected and processed by a specific processor, usually carried aboard the electric household appliance.
The transducers of the above-described type require to be firstly calibrated according to their transduction feature and then checked for such a feature to follow a curve which remains within predetermined tolerances, in order to limit measurement errors in use. Therefore, despite of performing a relatively long, complex step of calibrating, in any case the known analogue pressure sensors provide an inaccurate measurement, even though the inaccuracy is limited within predetermined tolerances.
In order to avoid or, at least, limit such a phenomenon, the transducer according to the aforesaid Italian patent application is provided onboard with an additional electronic circuit including a non-volatile memory unit for a series of corrective values to be applied to the values processed by the transducer, possibly provided with a microprocessor.
Similarly, U.S. Pat. No. 5,051,937 provides for fitting a complex electronic circuit provided with a sample capacitor aboard the sensor, which is able to correct the processed values on the basis of the simple frequency response of the sensor.
It is apparent that the known solutions briefly described above concerning the set forth technical problem are not satisfactory because they are complex, costly and have a large bulk.